The connection between near and far regions of the turbulent porous body wake

An experimental investigation of a porous body wake generated by a mesh strip was undertaken with a view of examining the evolution of coherent structures within the flow. The results indicate that, in contrast to a solid-body wake, the present porous body wake has an initial formation region where the small-scale vortices merge and the flow becomes gradually organized and more two-dimensional. This process continues until the flow reaches its “optimum” stage, where quasiperiodic, large-scale Karman-like spanwise structures are formed. Beyond this stage, the flow evolves in a fashion similar to other solid-body wakes, where the spanwise near-wake structures deform and double-roller structures emerge. The latter are most likely due to the evolution of the near-wake structures.